You would be right in CA too if it makes you feel any better...

Hand Signals. VC 22111

All required signals given by hand and arm shall be given in the following manner:

1. Left turn-hand and arm extended horizontally beyond the side of the bicycle.
2. Right turn- left hand and arm extended upward beyond the side of the bicycle or right hand and arm extended horizontally to the right side of the bicycle.
3. Stop or sudden decrease of speed signal- left hand and arm extended downward beyond the side of the bicycle.